A claim of trademark infringement can be responded to by either attacking plaintiff's own trademark rights or else denying the existence of trademark infringement or dilution. The defendant may be able to argue the following defenses: (1) plaintiff abandoned the mark; (2) plaintiff engaged in fraud when registering or maintaining registration of the mark; (3) the mark is generic (4) plaintiff engaged in trademark misuse by using exclusive rights in the mark to violate the law; (5) plaintiff delayed unreasonably before asserting or enforcing rights against defendant (laches) and therefore should be stopped form claiming infringement (estoppel); (6) the mark is functional; (7) plaintiff's explicit or implicit conduct reasonably offered assurances to defendant that plaintiff would permit defendant's use of the mark (acquiescence); (8) defendant is not using the mark as a trademark, but merely to describe defendant's own products (fair use); (9) defendant is not using the mark in a manner that is likely to cause confusion; (10) the First Amendment protects free expression, including certain uses of trademarks such as parody.
